| 1 |
/* Copyright (c) 1991 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* color.c - routines for color calculations. |
| 9 |
* |
| 10 |
* 10/10/85 |
| 11 |
*/ |
| 12 |
|
| 13 |
#include <stdio.h> |
| 14 |
|
| 15 |
#include "color.h" |
| 16 |
|
| 17 |
#define MINELEN 8 /* minimum scanline length for encoding */ |
| 18 |
#define MAXELEN 0x7fff /* maximum scanline length for encoding */ |
| 19 |
#define MINRUN 4 /* minimum run length */ |
| 20 |
|
| 21 |
#ifndef frexp |
| 22 |
extern double frexp(); |
| 23 |
#endif |
| 24 |
|
| 25 |
|
| 26 |
char * |
| 27 |
tempbuffer(len) /* get a temporary buffer */ |
| 28 |
unsigned len; |
| 29 |
{ |
| 30 |
extern char *malloc(), *realloc(); |
| 31 |
static char *tempbuf = NULL; |
| 32 |
static unsigned tempbuflen = 0; |
| 33 |
|
| 34 |
if (len > tempbuflen) { |
| 35 |
if (tempbuflen > 0) |
| 36 |
tempbuf = realloc(tempbuf, len); |
| 37 |
else |
| 38 |
tempbuf = malloc(len); |
| 39 |
tempbuflen = tempbuf==NULL ? 0 : len; |
| 40 |
} |
| 41 |
return(tempbuf); |
| 42 |
} |
| 43 |
|
| 44 |
|
| 45 |
fwritecolrs(scanline, len, fp) /* write out a colr scanline */ |
| 46 |
register COLR *scanline; |
| 47 |
unsigned len; |
| 48 |
register FILE *fp; |
| 49 |
{ |
| 50 |
register int i, j, beg, cnt; |
| 51 |
int c2; |
| 52 |
|
| 53 |
if (len < MINELEN | len > MAXELEN) /* OOBs, write out flat */ |
| 54 |
return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len); |
| 55 |
/* put magic header */ |
| 56 |
putc(2, fp); |
| 57 |
putc(2, fp); |
| 58 |
putc(len>>8, fp); |
| 59 |
putc(len&255, fp); |
| 60 |
/* put components seperately */ |
| 61 |
for (i = 0; i < 4; i++) { |
| 62 |
for (j = 0; j < len; j += cnt) { /* find next run */ |
| 63 |
for (beg = j; beg < len; beg += cnt) { |
| 64 |
for (cnt = 1; cnt < 127 && beg+cnt < len && |
| 65 |
scanline[beg+cnt][i] == scanline[beg][i]; cnt++) |
| 66 |
; |
| 67 |
if (cnt >= MINRUN) |
| 68 |
break; /* long enough */ |
| 69 |
} |
| 70 |
if (beg-j > 1 && beg-j < MINRUN) { |
| 71 |
c2 = j+1; |
| 72 |
while (scanline[c2++][i] == scanline[j][i]) |
| 73 |
if (c2 == beg) { /* short run */ |
| 74 |
putc(128+beg-j, fp); |
| 75 |
putc(scanline[j][i], fp); |
| 76 |
j = beg; |
| 77 |
break; |
| 78 |
} |
| 79 |
} |
| 80 |
while (j < beg) { /* write out non-run */ |
| 81 |
if ((c2 = beg-j) > 128) c2 = 128; |
| 82 |
putc(c2, fp); |
| 83 |
while (c2--) |
| 84 |
putc(scanline[j++][i], fp); |
| 85 |
} |
| 86 |
if (cnt >= MINRUN) { /* write out run */ |
| 87 |
putc(128+cnt, fp); |
| 88 |
putc(scanline[beg][i], fp); |
| 89 |
} else |
| 90 |
cnt = 0; |
| 91 |
} |
| 92 |
} |
| 93 |
return(ferror(fp) ? -1 : 0); |
| 94 |
} |
| 95 |
|
| 96 |
|
| 97 |
freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */ |
| 98 |
register COLR *scanline; |
| 99 |
int len; |
| 100 |
register FILE *fp; |
| 101 |
{ |
| 102 |
register int i, j; |
| 103 |
int code, val; |
| 104 |
/* determine scanline type */ |
| 105 |
if (len < MINELEN | len > MAXELEN) |
| 106 |
return(oldreadcolrs(scanline, len, fp)); |
| 107 |
if ((i = getc(fp)) == EOF) |
| 108 |
return(-1); |
| 109 |
if (i != 2) { |
| 110 |
ungetc(i, fp); |
| 111 |
return(oldreadcolrs(scanline, len, fp)); |
| 112 |
} |
| 113 |
scanline[0][GRN] = getc(fp); |
| 114 |
scanline[0][BLU] = getc(fp); |
| 115 |
if ((i = getc(fp)) == EOF) |
| 116 |
return(-1); |
| 117 |
if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) { |
| 118 |
scanline[0][RED] = 2; |
| 119 |
scanline[0][EXP] = i; |
| 120 |
return(oldreadcolrs(scanline+1, len-1, fp)); |
| 121 |
} |
| 122 |
if ((scanline[0][BLU]<<8 | i) != len) |
| 123 |
return(-1); /* length mismatch! */ |
| 124 |
/* read each component */ |
| 125 |
for (i = 0; i < 4; i++) |
| 126 |
for (j = 0; j < len; ) { |
| 127 |
if ((code = getc(fp)) == EOF) |
| 128 |
return(-1); |
| 129 |
if (code > 128) { /* run */ |
| 130 |
code &= 127; |
| 131 |
val = getc(fp); |
| 132 |
while (code--) |
| 133 |
scanline[j++][i] = val; |
| 134 |
} else /* non-run */ |
| 135 |
while (code--) |
| 136 |
scanline[j++][i] = getc(fp); |
| 137 |
} |
| 138 |
return(feof(fp) ? -1 : 0); |
| 139 |
} |
| 140 |
|
| 141 |
|
| 142 |
oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */ |
| 143 |
register COLR *scanline; |
| 144 |
int len; |
| 145 |
register FILE *fp; |
| 146 |
{ |
| 147 |
int rshift; |
| 148 |
register int i; |
| 149 |
|
| 150 |
rshift = 0; |
| 151 |
|
| 152 |
while (len > 0) { |
| 153 |
scanline[0][RED] = getc(fp); |
| 154 |
scanline[0][GRN] = getc(fp); |
| 155 |
scanline[0][BLU] = getc(fp); |
| 156 |
scanline[0][EXP] = getc(fp); |
| 157 |
if (feof(fp) || ferror(fp)) |
| 158 |
return(-1); |
| 159 |
if (scanline[0][RED] == 1 && |
| 160 |
scanline[0][GRN] == 1 && |
| 161 |
scanline[0][BLU] == 1) { |
| 162 |
for (i = scanline[0][EXP] << rshift; i > 0; i--) { |
| 163 |
copycolr(scanline[0], scanline[-1]); |
| 164 |
scanline++; |
| 165 |
len--; |
| 166 |
} |
| 167 |
rshift += 8; |
| 168 |
} else { |
| 169 |
scanline++; |
| 170 |
len--; |
| 171 |
rshift = 0; |
| 172 |
} |
| 173 |
} |
| 174 |
return(0); |
| 175 |
} |
| 176 |
|
| 177 |
|
| 178 |
fwritescan(scanline, len, fp) /* write out a scanline */ |
| 179 |
register COLOR *scanline; |
| 180 |
int len; |
| 181 |
FILE *fp; |
| 182 |
{ |
| 183 |
COLR *clrscan; |
| 184 |
int n; |
| 185 |
register COLR *sp; |
| 186 |
/* get scanline buffer */ |
| 187 |
if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
| 188 |
return(-1); |
| 189 |
clrscan = sp; |
| 190 |
/* convert scanline */ |
| 191 |
n = len; |
| 192 |
while (n-- > 0) { |
| 193 |
setcolr(sp[0], scanline[0][RED], |
| 194 |
scanline[0][GRN], |
| 195 |
scanline[0][BLU]); |
| 196 |
scanline++; |
| 197 |
sp++; |
| 198 |
} |
| 199 |
return(fwritecolrs(clrscan, len, fp)); |
| 200 |
} |
| 201 |
|
| 202 |
|
| 203 |
freadscan(scanline, len, fp) /* read in a scanline */ |
| 204 |
register COLOR *scanline; |
| 205 |
int len; |
| 206 |
FILE *fp; |
| 207 |
{ |
| 208 |
register COLR *clrscan; |
| 209 |
|
| 210 |
if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
| 211 |
return(-1); |
| 212 |
if (freadcolrs(clrscan, len, fp) < 0) |
| 213 |
return(-1); |
| 214 |
/* convert scanline */ |
| 215 |
colr_color(scanline[0], clrscan[0]); |
| 216 |
while (--len > 0) { |
| 217 |
scanline++; clrscan++; |
| 218 |
if (clrscan[0][RED] == clrscan[-1][RED] && |
| 219 |
clrscan[0][GRN] == clrscan[-1][GRN] && |
| 220 |
clrscan[0][BLU] == clrscan[-1][BLU] && |
| 221 |
clrscan[0][EXP] == clrscan[-1][EXP]) |
| 222 |
copycolor(scanline[0], scanline[-1]); |
| 223 |
else |
| 224 |
colr_color(scanline[0], clrscan[0]); |
| 225 |
} |
| 226 |
return(0); |
| 227 |
} |
| 228 |
|
| 229 |
|
| 230 |
setcolr(clr, r, g, b) /* assign a short color value */ |
| 231 |
register COLR clr; |
| 232 |
double r, g, b; |
| 233 |
{ |
| 234 |
double d; |
| 235 |
int e; |
| 236 |
|
| 237 |
d = r > g ? r : g; |
| 238 |
if (b > d) d = b; |
| 239 |
|
| 240 |
if (d <= 1e-32) { |
| 241 |
clr[RED] = clr[GRN] = clr[BLU] = 0; |
| 242 |
clr[EXP] = 0; |
| 243 |
return; |
| 244 |
} |
| 245 |
|
| 246 |
d = frexp(d, &e) * 256.0 / d; |
| 247 |
|
| 248 |
clr[RED] = r * d; |
| 249 |
clr[GRN] = g * d; |
| 250 |
clr[BLU] = b * d; |
| 251 |
clr[EXP] = e + COLXS; |
| 252 |
} |
| 253 |
|
| 254 |
|
| 255 |
colr_color(col, clr) /* convert short to float color */ |
| 256 |
register COLOR col; |
| 257 |
register COLR clr; |
| 258 |
{ |
| 259 |
double f; |
| 260 |
|
| 261 |
if (clr[EXP] == 0) |
| 262 |
col[RED] = col[GRN] = col[BLU] = 0.0; |
| 263 |
else { |
| 264 |
f = ldexp(1.0, (int)clr[EXP]-(COLXS+8)); |
| 265 |
col[RED] = (clr[RED] + 0.5)*f; |
| 266 |
col[GRN] = (clr[GRN] + 0.5)*f; |
| 267 |
col[BLU] = (clr[BLU] + 0.5)*f; |
| 268 |
} |
| 269 |
} |
| 270 |
|
| 271 |
|
| 272 |
bigdiff(c1, c2, md) /* c1 delta c2 > md? */ |
| 273 |
register COLOR c1, c2; |
| 274 |
double md; |
| 275 |
{ |
| 276 |
register int i; |
| 277 |
|
| 278 |
for (i = 0; i < 3; i++) |
| 279 |
if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) || |
| 280 |
colval(c2,i)-colval(c1,i) > md*colval(c1,i)) |
| 281 |
return(1); |
| 282 |
return(0); |
| 283 |
} |
